Flexible display unit and mobile terminal including same

ABSTRACT

The present disclosure provides a display unit including: a flexible display formed to be elastically deformable; and a flexible portion comprising a flexible frame coupled to the rear surface of the flexible display, wherein the flexible frame is configured to have first holes repeatedly formed therethrough such that the flexible frame can be bent maximally to a first curvature; and a rigid portion disposed on at least one side of the flexible portion, wherein the flexible frame is made of a titanium material.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a flexible display unit configured tobe elastically deformable between a flat state and a bent state at amaximum curvature, and a mobile terminal having the same.

2. Description of the Related Art

A portable electronic device (hereinafter, mobile terminal) such as acommunication terminal, a multimedia device, a portable computer, a gamemachine, and a photographing apparatus has a display for displayingimage information. The mobile terminal may have a folding structure thatcan be folded to a smaller size for convenience of carrying. In thistype of mobile terminal, two bodies are connected by a folding structure(for example, a hinge portion).

Displays in the related art have a non-foldable structure, and thus astructure in which a display is disposed over two whole bodies that arefoldably connected to each other cannot be implemented. Therefore, asubstantially large screen cannot be applied to a mobile terminal with afolding structure.

However, in recent years, as a flexible display capable of bending hasbeen developed, research has been carried out to apply a flexibledisplay to a mobile terminal having a folding structure. In this case, aflexible display may be disposed over two whole bodies across a foldingstructure, thereby implementing a large screen. However, even with aflexible display capable of bending, the flexible display itself may bebroken when it is completely bent (i.e., bent angularly), and thus astructure capable of limiting a curvature radius of the flexible displaywhen folding the mobile terminal is required.

In order to allow the flexible display to be bent at a preset curvature,a structure in which a flexible frame is laminated with a flexibledisplay is used. However, flexible frames developed until now has only astructure in which one portion thereof can be curved at a specificcurvature, but a structure in which two adjacent portions are connectedsmoothly while being configured to allow bending at different maximumcurvatures has not been proposed.

In particular, when the two adjacent portions have different curvatures,a breakage of the flexible display may occur due to a change incurvature at the boundary. Therefore, studies on a flexible framecapable of smoothly connecting two adjacent portions having differentcurvatures have been carried out.

On the other hand, stainless steel is generally used as the flexibleframe. However, stainless steel is not an optimal material from theviewpoint of restoration because the yield strain is not so large. Inparticular, in the case of a flexible frame made of stainless steel,when the flexible display is bent, it may not be flattened again,thereby causing a problem in which a surface of the flexible displayundulates like a wave.

In addition, when an impact is applied to the flexible display in casewhere the flexible frame is formed of a metal material, the flexibleframe may not absorb the impact, thereby causing a problem in which theflexible display is damaged.

SUMMARY OF THE INVENTION

A first object of the present disclosure is to provide a flexible framelaminated with a flexible display to bend two adjacent portions of theflexible display at different maximum curvatures in accordance withshape deformation.

A second object of the present disclosure is to provide a design methodcapable of adjusting a degree of bending and a repulsive force of theflexible frame.

A third object of the present disclosure is to provide a flexible framecapable of smoothly connecting two adjacent portions having differentcurvatures of a flexible display.

A fourth object of the present disclosure is to provide a flexible framecapable of restoring a flexible display to a flat state even when thebending and restoration of the flexible display are repeated, therebyallowing the flexible display to be flattened all the time.

A fifth object of the present disclosure is to provide a laminatedstructure of a flexible display and a flexible frame capable ofabsorbing an impact applied to the flexible display.

In order to accomplish the first object of the present disclosure, aflexible frame may be provided with a flexible region, and the flexibleregion may include a first flexible portion having first holes formedrepeatedly and bendable up to a state having a maximum first curvature;and a second flexible portion having second holes formed repeatedly inparallel to the first holes, and bendable up to a state having a maximumsecond curvature, wherein a total area occupied by the first holes perunit area in the first flexible portion is larger than a total areaoccupied by the second holes per unit area in the second flexibleportion, so that the first curvature is larger than the secondcurvature.

The first holes may be repeatedly formed along a widthwise direction anda lengthwise direction of the flexible region which intersect with eachother, wherein the second holes are repeatedly formed along thewidthwise direction and the lengthwise direction of the flexible regionwhich intersect each other.

The first holes may be arranged in a zigzag form while partiallyoverlapping each other along the lengthwise direction of the flexibleregion, wherein the second holes are arranged in a zigzag form whilepartially overlapping each other along the lengthwise direction of theflexible region.

A length of each overlapped portion of the first holes may be longerthan a length of each overlapped portion of the second holes.

The first holes and the second holes respectively may include aplurality of holes having the same size and spaced apart from oneanother at preset intervals.

The first holes and the second holes may further include respectivelyanother hole having at least one of a size and a spaced intervaldifferent from those of the plurality of holes.

The second object of the present disclosure may be accomplished byadjusting a total area occupied by holes per unit area in each flexibleportion.

The third object of the present disclosure may be accomplished by aconnecting portion having third holes formed repeatedly between thefirst flexible portion and the second flexible portion in parallel tothe first and second holes.

A total area occupied by the third holes per unit area in the connectingportion may be smaller than the total area occupied by the first holesper unit area in the first flexible portion and larger than the totalarea occupied by the second holes per unit area in the second flexibleportion.

A length of each of the third holes may be shorter than a length of thefirst hole and longer than a length of the second hole.

The length of each of the third holes may gradually decrease from thefirst flexible portion toward the second flexible portion.

The third holes may be arranged in a zigzag form while partiallyoverlapping each other along the lengthwise direction of the flexibleregion, and wherein a length of each overlapped portion of the thirdholes may be shorter than a length of each overlapped portion of thefirst holes and longer than a length of each overlapped portion of thesecond holes.

A length of each overlapped portion of the third holes may graduallydecrease from the first flexible portion toward the second flexibleportion.

The third object of the present disclosure may be accomplished by aboundary portion having fourth holes formed repeatedly between thesecond flexible portion and a rigid portion, the rigid portion locatedon one side of the second flexible portion.

A total area occupied by the fourth holes per unit area in the boundaryportion is smaller than the total area occupied by the second holes perunit area in the second flexible portion.

A length of each of the fourth holes may be shorter than a length of thesecond hole.

A length of a hole of the fourth holes, the hole adjacent to the rigidportion, may be shorter than a length of another hole of the fourthholes, the another hole adjacent to the second flexible portion.

The fourth holes may be arranged in a zigzag form while partiallyoverlapping each other along the lengthwise direction of the flexibleregion, wherein a length of each overlapped portion of the fourth holesis shorter than a length of each overlapped portion of the second holes.

In order to accomplish the fourth object of the present disclosure, aflexible display unit of the present disclosure may include a flexibledisplay formed to be elastically deformed; and a flexible frame coupledto a rear surface of the flexible display, wherein the flexible frameincludes a flexible portion in which first holes are repeatedly formedto be bendable up to a state having a maximum first curvature; and arigid portion disposed on at least one side of the flexible portion, andthe flexible frame is formed of a titanium material.

When the flexible display is deformed, an interval between the firstholes may be enlarged or reduced to apply a restoring force to theflexible display.

An adhesive portion may be disposed between the flexible display and theflexible frame, and a part of the adhesive portion may be exposedrearward through the first holes.

In order to accomplish the fifth object of the present disclosure, theflexible display unit of the present disclosure may include an adhesiveportion disposed on a rear surface of the flexible display; and asilicon portion disposed between the adhesive portion and the flexibleframe, wherein the silicon portion includes a first portion disposed onthe flexible portion and the rigid portion; and a second portion filledin the first holes.

The second portion may form the same plane as the rear surface of theflexible frame. The silicon portion may be integrally formed with theflexible frame by insert injection.

Alternatively, the flexible display unit of the present disclosure mayfurther include an adhesive portion disposed between the flexibledisplay and the flexible frame; and a silicon portion filled in thefirst holes.

The silicon portion may be brought into contact with a part of theadhesive portion exposed through the first holes.

The silicon portion may form the same plane as the rear surface of theflexible frame.

The silicon portion may be integrally formed with the flexible frame byinsert injection.

On the other hand, the present disclosure may include a flexible displayformed to be elastically deformed; and a flexible frame coupled to arear surface of the flexible display, wherein the flexible frameincludes a first flexible portion in which first holes are repeatedlyformed to be bendable up to a state having a maximum first curvature; asecond flexible portion in which second holes parallel to the firstholes are repeatedly formed on one side of the first flexible portion,and configured to be bendable up to a state having a maximum secondcurvature; and a third flexible portion in which third holes parallel tothe first holes are repeatedly formed on the other side of the firstflexible portion, and configured to be bendable up to a state having amaximum third curvature; and wherein the first curvature is at least twotimes the second and third curvatures.

Moreover, the present disclosure discloses a mobile terminal, includinga terminal body formed of an elastically deformable material, a flexibledisplay unit coupled to one surface of the terminal body and configuredto be elastically deformable together with the terminal body; and magnetportions provided at both ends of the terminal body disposed to faceeach other in a state where the first to third flexible portions arebent at the first to third curvatures, respectively, to exert attractiveforces on each other.

The effects of the present disclosure obtained through theabove-mentioned solution are as follows.

First, a total area occupied by the first holes per unit area in thefirst flexible portion is designed to be larger than a total areaoccupied by the second holes per unit area in the second flexibleportion, thereby implementing a flexible frame that is bendable at alarger curvature in the first flexible portion than the second flexibleportion. Therefore, the flexible frame may be laminated with a flexibledisplay, thereby implementing a flexible display unit in which twoadjacent portions are bent at different maximum curvatures.

Second, since a repulsive force to be restored increases as increasing adegree of bending, and a total area occupied by the holes per unit areain each flexible portion may be adjusted to adjust a degree of bendingand a repulsive force of the flexible display unit.

Third, a connecting portion may be formed between two flexible portionsthat is bendable at different maximum curvatures or a boundary portionmay be formed between a flexible portion and a rigid portion, therebyimplementing a flexible display unit in which two adjacent portionshaving different curvatures are connected smoothly.

Fourth, when titanium having a lower yield strength compared tostainless steel but having a predetermined level of yield strength and alarge yield strain is used for a flexible frame, the flexible displaymay be restored to a flat state all the time, thereby preventing thephenomenon of undulating like a wave. Therefore, the reliability of theflexible display unit can be improved.

Fifth, since a silicon portion may be provided between the flexibledisplay and the flexible frame to elastically support the flexibledisplay, thereby absorbing an impact transmitted to the flexible displayat a predetermined level. Moreover, since the silicon portion is filledin the holes of the flexible frame, a restoring force of the siliconportion may be added to a restoring force of the flexible frame itself,thereby increasing a total restoring force.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a view showing an example of a flexible frame of the presentdisclosure;

FIG. 2 is a conceptual view showing a state in which each flexibleportion of the flexible frame shown in FIG. 1 is bent at a maximumcurvature;

FIG. 3 is a conceptual view showing a Y direction area change of theflexible frame shown in FIG. 1;

FIG. 4 is an enlarged view of a flexible region shown in FIG. 1;

FIG. 5 is an enlarged view of a first flexible portion shown in FIG. 4;

FIG. 6 is a conceptual view for explaining an X direction arrangementform of holes applied to the first flexible portion shown in FIG. 5;

FIG. 7 is a conceptual view for explaining an X direction arrangementform of holes applied to the first flexible portion shown in FIG. 5;

FIG. 8 is a conceptual view for explaining that the first flexibleportion shown in FIG. 5 can have a symmetrical shape with respect to theX and Y axes;

FIG. 9 is an enlarged view of a connecting portion shown in FIG. 4;

FIG. 10 is a conceptual view showing an example of a boundary portionshown in FIG. 4;

FIG. 11 is a conceptual view showing another example of a boundaryportion shown in FIG. 4;

FIG. 12 is a conceptual view showing an example of a flexible displayunit having a flexible frame according to the present disclosure;

FIG. 13 is a conceptual view showing another example of a flexibledisplay unit having a flexible frame according to the presentdisclosure;

FIG. 14 is a conceptual view showing still another example of a flexibledisplay unit having a flexible frame according to the presentdisclosure;

FIG. 15 is a conceptual diagram for explaining a restoring mechanism ofa flexible display unit by combining a flexible display with a flexibleframe according to the present disclosure;

FIG. 16 is a conceptual view illustrating an example of a mobileterminal to which a flexible display unit having the flexible frameshown in FIG. 1 is applied;

FIG. 17 is a view showing another example of a flexible frame of thepresent disclosure;

FIG. 18 is a conceptual view showing a state in which a flexible portionof the flexible frame shown in FIG. 17 is bent at a maximum curvature;

FIG. 19 is a conceptual view showing a Y direction area change of theflexible frame shown in FIG. 17;

FIG. 20 is an enlarged view of a flexible region shown in FIG. 17;

FIG. 21 is a conceptual view illustrating an example of a mobileterminal to which a flexible display unit having the flexible frameshown in FIG. 17 is applied;

FIG. 22 is a conceptual view showing an example of a mobile terminal towhich a flexible display unit having another example of the flexibleframe of the present disclosure is applied; and

FIG. 23 is a conceptual view showing still another example of a flexibleframe of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a flexible frame according to the present invention and aflexible display unit having the same will be described in detail withreference to the drawings.

In describing the embodiments disclosed herein, moreover, the detaileddescription will be omitted when a specific description for publiclyknown technologies to which the invention pertains is judged to obscurethe gist of the present invention.

The accompanying drawings are used to help easily understand varioustechnical features and it should be understood that the embodimentspresented herein are not limited by the accompanying drawings. As such,the present disclosure should be construed to extend to any alterations,equivalents and substitutes in addition to those which are particularlyset out in the accompanying drawings.

In the following description, a singular representation may include aplural representation as far as it represents a definitely differentmeaning from the context.

FIG. 1 is a view showing an example of a flexible frame 100 of thepresent disclosure, and FIG. 2 is a conceptual view showing a state inwhich each flexible portion of the flexible frame 100 shown in FIG. 1 isbent at a maximum curvature, and FIG. 3 is a conceptual view showing a Ydirection area change of the flexible frame 100 shown in FIG. 1, andFIG. 4 is an enlarged view of a flexible region 110 shown in FIG. 1.

In the following description, the X direction corresponds to a widthwisedirection of the flexible frame 100, and the Y direction corresponds toa lengthwise direction of the flexible frame 100.

Referring to FIGS. 1 to 4, the flexible frame 100 includes the flexibleregion 110 that is bendable at least at a maximum curvature. Theflexible region 110 may include flexible portions that is bendable atdifferent maximum curvatures. The flexible portions may be sequentiallydisposed along one direction (Y direction in the drawing) of theflexible frame 100, so that the flexible frame 100 can be bent withrespect to one direction.

In this example, the flexible region 110 includes a first flexibleportion 111 that is bendable up to a state having a maximum firstcurvature and a second flexible portion 112 that is bendable up to astate having a maximum second curvature. As shown in the drawing, twosecond flexible portions 112 may be provided, and disposed on both sidesof the first flexible portion 111 in the Y direction.

First holes 111′ are repeatedly formed on the first flexible portion 111to implement the bending of the first flexible portion 111. In otherwords, flexibility may be generated on the first flexible portion 111due to the first holes 111′, and the first flexible portion 111 may bebent up to a state having the maximum first curvature.

The first holes 111′ are repeatedly formed along the X and Y directionsintersecting each other. The first holes 111′ are elongated in the Xdirection.

Similarly, second holes 112′ are repeatedly formed on the secondflexible portion 112 to implement the bending of the second flexibleportion 112. In other words, flexibility may be generated on the firstflexible portion 112 due to the first holes 112′, and the first flexibleportion 112 may be bent up to a state having the maximum firstcurvature. Here, the second curvature has a curvature different from thefirst curvature.

The second holes 112′ are formed parallel to the first holes 111′ sothat the second flexible portion 112 can be bent with respect to the Ydirection together with the first flexible portion 111. The second holes112′ are respectively formed in a repetitive manner along the X and Ydirections intersecting each other. The second holes 112′ are extendedin an elongated manner in the X direction.

In this example, the first curvature is greater than the secondcurvature. In other words, the first flexible portion 111 is configuredto be more bendable than the second flexible portion 112. Therefore,while the first and second flexible portions 111, 112 are bent at thefirst and second curvatures, respectively, a repulsive force acting onthe first flexible portion 111 is greater than that acting on the secondflexible portion 112.

In FIG. 2, it is shown that the first and second flexible portions 111,112 are bent to the maximum. Since the reciprocal of the curvature is acurvature radius, a curvature radius (R1) of the first flexible portion111 is smaller than a curvature radius (R2) of the second flexibleportion 112 in this state. The center (0) of the curvature radius (R1)of the first flexible portion 111 is located in an inner space formed bythe folding of the flexible frame 100, and the center (O′, O″) of thecurvature radius of the second flexible portion 112 is located in anouter space formed by the folding of the flexible frame 100.

A rigid portion 120 is disposed on one side of each second flexibleportion 112 in the Y direction. The rigid portion 120, as a portion thatis hardly bent by an external force, may be formed in a plane. The rigidportion 120 is not formed with holes intended to implement bending.

As described above, the rigid portion 120 and the first flexible portion111 are disposed on both sides of the second flexible portion 112 in theY direction. In a state where the first and second flexible portions111, 112 are bent to the maximum, the rigid portions 120 are arranged toface each other.

Referring to FIG. 3, the larger a total area occupied by the holes perunit area of the flexible portion, the more flexible the flexibleportion becomes. In other words, the smaller a total area occupied by aninherently rigid material per unit area of the flexible portion, themore flexible the flexible portion becomes. It means that a maximumcurvature of the flexible portion can be adjusted by changing a totalarea occupied by the holes per unit area of the flexible portion atdesign time.

In this manner, a total area occupied by the first holes 111′ per unitarea in the first flexible portion 111 is greater than a total areaoccupied by the second flexible portions 111 per unit area in the secondflexible portion 111 so that the first flexible portion 111 is morebendable than the second flexible portion 112.

As described above, the second flexible portion 112 is disposed on bothsides of the first flexible portion 111, respectively, in the Ydirection, and the rigid portion 120 is provided on one side of eachsecond flexible portion 112 in the Y direction.

A connecting portion 113 for smoothly connecting the first flexibleportion 111 and the second flexible portion 112 is formed between thefirst flexible portion 111 and the second flexible portion 112.Similarly, a boundary portion 114 for smoothly connecting the firstflexible portion 112 and the second flexible portion 120 is formedbetween them.

In other words, the rigid portion 120, the boundary portion 114, thesecond flexible portion 112, the connecting portion 113, the firstflexible portion 111, the connecting portion 113, the second flexibleportion 112, the boundary portion 114, and the rigid portion 120 aresequentially arranged on the flexible frame 100.

Hereinafter, each of the portions will be described in more detail.

For reference, only the first flexible portion 111 and the secondflexible portion 112 are formed in such a manner that a total areaoccupied by the first holes 111′ per unit area is larger than a totalarea occupied by the second holes 112′, but there is substantially nodifference in the arrangement of the first hole 111′ and the second hole112′. Therefore, the description of the first flexible portion 111 withreference to FIGS. 5 to 8 below may be applied as it is to the secondflexible portion 112 as it is.

FIG. 5 is an enlarged view of the first flexible portion 111 shown inFIG. 4.

Referring to FIG. 5, the first holes 111′ formed in the first flexibleportion 111 are repeatedly formed along the X and Y directionsintersecting each other. The first holes 111′ formed in the firstflexible portion 111 are formed in an elongated manner in the Xdirection so that the first flexible portion 111 is bendable withrespect to the Y direction.

The first holes 111′ may be formed in a recessed shape at both endportions of the flexible frame 100 in the X direction. The first holes111′ having such a shape may be formed one by one along the Y direction.

The first holes 111′ are arranged in a zigzag manner while partiallyoverlapping each other along the Y direction. As shown in the drawing,the first holes 111′ arranged along the X direction are disposeddirectly in the Y direction above or below a region between the firstholes 111′ arranged along the X direction (a region where an inherentmaterial of the rigid flexible frame 100 remains, hereinafter referredto as a “link”).

As described above, the second holes 112′ having the same shape as thefirst holes 111′ formed on the first flexible portion 111 may be alsoformed on the the second flexible portion 112. However, a length of amutually overlapping portion between the second holes 112′ is designedto be shorter than that of a mutually overlapping portion between thefirst holes 111′.

A repulsive force per unit area of the link may be calculated by thefollowing equation.

$T = \frac{\theta \; {GJ}^{\prime}}{l}$

-   -   T=Repulsive force (Torque) (Nm)    -   l=Length (m) where holes are overlapped along the Y direction    -   G=Modulus of rigidity (N/m2)    -   J′=Polar moment of inertia (m4)    -   θ=Bent angle per link (radians)

$\theta = \frac{\Theta ({Total})}{n}$

-   -   n=Number of links formed along the Y direction    -   Θ(Total)=Angle bent to the maximum (radians)

In other words, as an overlapping length of the holes increases alongthe Y direction, a repulsive force decreases, and as a bent angle of perlink increases, a repulsive force increases.

As a result of the simulation, a bent angle per link in the firstflexible portion 111 is overwhelmingly larger than a bent angle per linkin the second flexible portion 112 (approximately 20 times), and thus itcan be seen that a larger repulsive force acts on the first flexibleportion 111 though a length where the holes are overlapped along the Ydirection is shorter in the first flexible portion 111.

On the other hand, since the links are arranged along the X direction,the repulsive force increases in proportion to a number of the arrangedlinks. In this example, since the number of links arranged in the Xdirection is the same for both the first flexible portion 111 and thesecond flexible portion 112, it can be seen that there is no greatinfluence on the mutual comparison of the repulsive forces is.

FIG. 6 is a conceptual view for explaining the X direction arrangementof the first holes 111′ applied to the first flexible portion 111 shownin FIG. 5.

Referring to FIG. 6A, the first holes 111′ may include a plurality ofholes 111′a arranged at preset intervals along the X direction whilehaving the same width (X direction).

As shown in the drawing, each of the plurality of holes 111′a may have awidth (A) and may be spaced apart from each other with a spacinginterval (B) therebetween. As described above, the plurality of holes111′a may have a repeated shape according to a constant reference (widthand spacing interval).

In some embodiments, the flexible portions may include perforations toallow for bending of the frame which do not correspond to fully definedholes or openings. For example, a perforation may correspond to apuncture in a particular pattern where the material of the flexibleframe is punctured or cut to allow for flexing of the frame at thepuncture or cut location. The perforation may not correspond to anymaterial removed from the frame, and the material of the frame may beleft attached where the puncture or cut is located. Other embodimentsmay include a combination of an opening or a hole where material of theframe is actually removed (or formed to not include such portions) alongwith a perforation or cut of the material adjacent to the opening orhole. In other embodiments, an opening or hole may have a concaveportion, where the material of the frame juts into the opening or holearea to define a “dent” in the opening or hole. It will be appreciatedthat all of these various embodiments are considered in this disclosureand may be combinable with any other configuration discussed herein.

Referring to FIG. 6B, the first holes 111′ may further include a hole111′b that is different in at least one of width and spacing intervalfrom the plurality of holes 111′a.

As shown in the drawing, at least one hole 111′b that is different in atleast one of width and spacing from the plurality of holes 111′a may beadded between the plurality of holes 111′a having a width (A) and beingspaced apart from each other with a spacing interval (B) therebetween.The added hole 111′b has a width (A′), and the width (A′) has a valuesmaller or larger than the width (A). Furthermore, a spacing interval(B′) between the added hole 111′b and one of the plurality of holes111′a repeatedly disposed adjacent thereto according to a predeterminedreference has a value smaller or larger than the spacing distance (B).

In this drawing, it is seen that a hole 111′b having a left-rightspacing interval (B′) and a width (A′) is added between a plurality ofholes 111′a repeatedly arranged according to a predetermined reference.The left and right spacing intervals may be of course set differentlyfrom each other.

By adding the holes described above, the maximum curvature or repulsiveforce of the first flexible portion 111 may be adjusted. For example,when the spacing interval (B′) is increased beyond the spacing interval(B) or the width (A′) is reduced from the width (A), the maximumcurvature of the first flexible portion 111 may be reduced, andaccordingly the repulsive force acting thereon may be reduced. On thecontrary, when the spacing interval (B′) is reduced from the spacinginterval (B) or the width (A′) is increased beyond the width (A), themaximum curvature of the first flexible portion 111 may be increased,and accordingly the repulsive force acting thereon may be increased.

FIG. 7 is a conceptual view for explaining the Y direction arrangementof the first holes 111′ applied to the first flexible portion 111 shownin FIG. 5.

Referring to FIG. 7A, the first holes 111′ may include a plurality ofholes 111′c arranged at preset intervals along the Y direction whilehaving the same length (Y direction).

As shown in the drawing, each of the plurality of holes 111′c may have alength (C) and may be spaced apart from each other with a spacinginterval (D) therebetween. As described above, the plurality of holes111′c may have a repeated shape according to a constant reference(length and spacing interval).

Referring to FIG. 7B, the first holes 111′ may further include a hole111′d that is different in at least one of length and spacing intervalfrom the plurality of holes 111′c.

As shown in the drawing, a hole 111′d that is different in at least oneof length and spacing interval from the plurality of holes 111′c may beadded between the plurality of holes 111′c having a length (C) and beingspaced apart from each other with a spacing interval (D) therebetween.The added hole 111′d has a length (C′) and the length C′ has a valuesmaller or larger than the length (C). Furthermore, a spacing interval(D′) between the added hole 111′d and one of the plurality of holes111′c repeatedly disposed adjacent thereto according to a predeterminedreference has a value smaller or larger than the spacing distance (D).

In this drawing, it is seen that a hole 111′d having a left-rightspacing interval (D′) and a length (C′) is added between a plurality ofholes 111′c repeatedly arranged according to a predetermined reference.The left and right spacing intervals may be of course set differentlyfrom each other.

By adding the holes described above, the maximum curvature or repulsiveforce acting on the first flexible portion 111 may be adjusted. Forexample, when the spacing interval (D′) is increased beyond the spacinginterval (D) or the length (C′) is reduced from the length (C), themaximum curvature of the first flexible portion 111 may be reduced, andaccordingly the repulsive force acting thereon may be reduced. On thecontrary, when the spacing interval (D′) is reduced from the spacinginterval (D) or the length (C′) is increased beyond the length (C), themaximum curvature of the first flexible portion 111 may be increased,and accordingly the repulsive force acting thereon may be increased.

In summary, the first and second holes 111′, 112′ include a plurality ofholes arranged at the same size and at predetermined intervals. Here,the same size denotes that the width (X direction) and the length (Ydirection) are the same. In some cases, a hole that is to different inat least one of size or spacing interval from the plurality of holes maybe added between the plurality of holes.

FIG. 8 is a conceptual view for explaining that the first flexibleportion shown in FIG. 5 can have a symmetrical shape with respect to theX and Y axes.

Referring to FIG. 8, the first flexible portion 111 may have asymmetrical shape with respect to an axis (X-axis) in the X directionpassing through the center. Accordingly, in a state where the firstflexible portion 111 is bent with respect to the Y direction, the firstflexible portion 111 may have a symmetrical shape about the X-axis.

Similarly, the first flexible portion 111 may have a symmetrical shapewith respect to an axis (Y-axis) in the Y direction passing through thecenter. Accordingly, in a state where the first flexible portion 111 isbent with respect to the Y direction, the first flexible portion 111 maymaintain a uniform shape in the X direction.

When the first flexible portion 111 and the second flexible portion 112are formed successively as the first flexible portion 111 and the secondflexible portion 112 are configured to be bendable at different maximumcurvatures, the flexible frame 100 may be damaged due to a change ofcurvature at the boundary. Hereinafter, a structure in which adjacentfirst and second flexible portions 111, 112 having different curvaturescan be smoothly connected will be described.

FIG. 9 is an enlarged view of a connecting portion 113 shown in FIG. 4.

Referring to FIG. 9, the connecting portion 113 for smoothly connectingthe first flexible portion 111 and the second flexible portion 112 isformed between the first flexible portion 111 and the second flexibleportion 112. Third holes 113′ parallel to the first and second holes111′, 112′ are repeatedly formed on the connecting portion 113 so thatthe connecting portion 113 can be bent in the Y direction. The firstholes 113′ are formed in an elongated manner in the X direction.

A degree of bending of the connecting portion 113 may be adjusted bychanging a total area occupied by the third holes 113′ per unit area ofthe connecting portion 113 as described above with respect to the firstand second flexible portions 111, 112.

The connecting portion 113 is configured to be less bendable than thefirst flexible portion 111 and more bendable than the second flexibleportion 112. To this end, a total area occupied by the third holes 113′per unit area in the connecting portion 113 is set to be smaller than atotal area occupied by the first holes 111′ per unit area in the firstflexible portion 111, and larger than a total area occupied by thesecond holes 112′ per unit area in the flexible portion 112.

For this purpose, a length of each of the third holes 113′ may be set tobe smaller than that of the first holes 111′ and greater than that ofthe second holes 112′. Alternatively, a spacing interval between thethird holes 113′ may be set to be larger than that between the firstholes 111′ and smaller than that between the second holes 112′.

The third holes 113′ are arranged in a zigzag manner while partiallyoverlapping each other along the Y direction. As shown in the drawing,the third holes 113′ arranged along the X direction are disposed in theY direction directly above or below a region between the third holes113′ arranged along the X direction (a region where an inherent materialof the rigid flexible frame 100 remains).

Here, a length of a mutually overlapping portion between the third holes113′ along the Y direction is set to be smaller than that of a mutuallyoverlapping portion between the first holes 111′ and larger than that ofa mutually overlapping portion between the second holes 112′.

The connecting portion 113 may be configured such that a degree ofbending gradually decreases from the first flexible portion 111 to thesecond flexible portion 112. In this case, a maximum curvature at oneend portion of the connecting portion 113 adjacent to the first flexibleportion 111 may be set to be larger than that at the other end portionof the connecting portion 113 adjacent to the second flexible portion112. In other words, the maximum curvature at one end portion of theconnecting portion 113 may be set to be smaller than the firstcurvature, and the maximum curvature at the other end portion of theconnecting portion 113 may be set to be larger than the secondcurvature.

For this purpose, a length of each of the third holes 113′ may be set togradually decrease from the first flexible portion 111 to the secondflexible portion 112. Here, a degree of reduction of the length of thethird holes 113′ may have a constant value (a). Alternatively, aninterval spaced between the third holes 113′ may be set to graduallyincrease from the first flexible portion 111 to the second flexibleportion 112. Here, a degree of increase in the spacing interval betweenthe third holes 113′ may have a constant value.

Moreover, a length of a mutually overlapping portion between the thirdholes 113′ may be set to gradually decrease from the first flexibleportion 111 to the second flexible portion 112 in the Y direction.

Similarly to the connecting portion 113 for smoothly connecting thefirst flexible portion 111 and the second flexible portion 112, aboundary portion 114 is provided even between the second flexibleportion 112 and the rigid portion 120. Hereinafter, a structure in whichadjacent second flexible portion 112 and rigid portion 120 havingdifferent curvatures can be smoothly connected will be described.

FIG. 10 is a conceptual view showing an example of the boundary portion114 shown in FIG. 4.

Referring to FIG. 10, the connecting portion 114 for smoothly connectingthe second flexible portion 112 and the rigid portion 120 is formedbetween them. The fourth holes 114′ are repeatedly formed on theboundary portion 114 so that the boundary portion 114 can be bent in theY direction. The fourth holes 114′ may be extended in an elongatedmanner in the X direction and disposed in parallel with the second holes112′.

A degree of bending of the boundary portion 114 may be adjusted bychanging a total area occupied by the fourth holes 114′ per unit area ofthe boundary portion 114 as described above with respect to theconnecting portion 113.

The boundary portion 114 is configured to be less bendable than secondflexible portion 112. For this purpose, a total area occupied by thefourth holes 114′ per unit area in the boundary portion 114 is set to besmaller than a total area occupied by the second holes 112′ per unitarea in the second flexible portion 112.

For this purpose, a length of each of the fourth holes 114′ may be setto be smaller than that of the second holes 112′. Alternatively, aspacing interval between the fourth holes 114′ may be set to be largerthan that between the second holes 112′.

The fourth holes 114′ may be arranged in a zigzag manner while partiallyoverlapping each other along the Y direction. As shown in the drawing,the fourth holes 114′ arranged along the X direction are disposed in theY direction directly above or below a region between the fourth holes114′ arranged along the X direction (a region where an inherent materialof the rigid flexible frame 100 remains).

Here, a length of a mutually overlapping portion between the fourthholes 114′ along the Y direction is set to be smaller than that of amutually overlapping portion of the second holes 112′.

A maximum curvature at one end portion of the boundary portion 114adjacent to the second flexible portion 112 may be set to be larger thanthat at the other end portion of the boundary portion 114 adjacent tothe rigid portion 120. In other words, the maximum curvature at one endportion of the boundary portion 114 may be set to be smaller than thesecond curvature, and the maximum curvature at the other end portion ofthe boundary portion 114 may be set to be larger than zero.

For this purpose, a length of a hole adjacent to the second flexibleportion 112 among the fourth holes 114′ may be set to be larger thanthat of a hole adjacent to the rigid portion 120. Alternatively, aspacing interval between the fourth holes 114′ in a portion adjacent tothe second flexible portion 112 may be set to be smaller than thatbetween the fourth holes 114′ in a portion adjacent to the rigid portion120.

FIG. 11 is a conceptual view showing another example of the boundaryportion 114 shown in FIG. 4.

Referring to FIG. 11, similarly to the previous example, the fourthholes 214′ are repeatedly formed on the boundary portion 214 so that theboundary portion 214 can be bent in the Y direction. The fourth holes214′ may be extended in an elongated manner in the X direction anddisposed in parallel with the second holes 212′.

The boundary portion 214 is configured to be less bendable than secondflexible portion 212. For this purpose, a total area occupied by thefourth holes 214′ per unit area in the boundary portion 214 is set to besmaller than a total area occupied by the second holes 212′ per unitarea in the second flexible portion 212.

However, the fourth holes 214′ for implementing this may be randomlyarranged. In other words, the fourth holes 214′ may be randomly arrangedunder the condition that a total area occupied by the fourth holes 214′per unit area in the boundary section 214 is set to be smaller than atotal area occupied by the second holes 212′ per unit area in the secondflexible portion 212.

A maximum curvature at one end portion of the boundary portion 214adjacent to the second flexible portion 212 may be set to be larger thanthat at the other end portion of the boundary portion 214 adjacent tothe rigid portion 220. In other words, the maximum curvature at one endportion of the boundary portion 214 may be set to be smaller than thesecond curvature, and the maximum curvature at the other end portion ofthe boundary portion 214 may be set to be larger than zero.

For this purpose, a total area occupied by the fourth holes 214′ perunit area at one end portion of the boundary portion 214 adjacent to thesecond flexible portion 212 may be set to be greater than a total areaoccupied by the fourth holes 214′ per unit area at the other end portionof the boundary portion 214 adjacent to the rigid portion 220. In otherwords, a degree of bending of the boundary portion 214 may be adjustedin such a manner that a total area occupied by an inherent rigidmaterial per unit area of the boundary portion 214 is greater at one endportion than at the other end portion of the boundary portion 214.

FIG. 12 is a conceptual view showing an example of a flexible displayunit 10 having the flexible frame 100 of the present disclosure.

Referring to FIG. 12, the flexible display unit 10 is formed in anelastically deformable manner, and includes a flexible display 11 andthe foregoing flexible frame 100.

The flexible display 11 is formed to be elastically deformable by anexternal force. The flexible display 11 may be configured to allow atouch input.

The flexible frame 100 is coupled to a rear surface of the flexibledisplay 11. The flexible display 11 is disposed to cover the rigidportion 120 and the flexible region 110 of the flexible frame 100.Therefore, when the flexible region 110 is bent, the flexible display 11is also bent, and when the flexible region 110 is restored, the flexibledisplay 11 is also restored.

At least one or more flexible portions may be provided in the flexibleregion 110. When a plurality of flexible portions are provided, they maybe configured to be bendable up to a state having different maximumcurvatures.

Various laminated structures may be applied to the flexible display 11and the flexible frame 100. For example, as shown in FIG. 12, theflexible display 11 and the flexible frame 100 may be coupled by abonding portion 12 interposed therebetween. For the bonding portion 12,an OCA (optically clear adhesive) may be used. In the above structure, apart of the bonding portion 12 is exposed through holes formed on theflexible portion in a rearward direction, that is, onto a rear surfaceof the flexible frame 100.

According to the above structure, it is advantageous in that a laminatedstructure of the flexible display 11 and the flexible frame 100 may beimplemented at a low cost, and a thickness of the flexible display unit10 can be made slim.

FIG. 13 is a conceptual view showing another example of a flexibledisplay unit 20 having the flexible frame 100 of the present disclosure.

Referring to FIG. 13, a bonding portion 22 is attached to a rear surfaceof the flexible display 21. For the bonding portion 22, an OCA(optically clear adhesive) may be used.

Between the bonding portion 22 and the flexible frame 100, a siliconportion 23 with an elastically deformable material is disposed. Thesilicon portion 23 includes a first portion 23 a disposed on theflexible region 110 and the rigid portion 120 and a second portion 23 bfilled between the holes 110′. Here, the first portion 23 a and thesecond portion 23 b are integrally formed.

The first portion 23 a of the silicon portion 23 is provided between theflexible display 21 and the flexible frame 100 to elastically supportthe flexible display 21. Therefore, an impact transmitted to theflexible display 21 may be absorbed to a determined level by the firstportion 23 a.

The second portion 23 b is exposed through the holes 110′ of theflexible region 110 in a rearward region, that is, onto a rear surfaceof the flexible frame 100. As shown in the drawing, the second portion23 b may form the same plane as the rear surface of the flexible frame100.

The silicon portion 23 may be integrally formed with the flexible frame100 by insert injection. The silicon part 23 is formed integrally withthe flexible frame 100, thereby allowing the silicon portion 23 toincrease a restoring force of the flexible frame 100 itself. In otherwords, in this laminated structure, a restoring force of the flexibleportion 100 acts on a restoring force of the silicon portion 23 at thesame time. Therefore, this laminated structure has a larger restoringforce compared to the laminated structure shown in FIG. 12.

In addition, the silicon portion 23 is configured to prevent theflexible frame 100 from being deformed by repeated bending. Therefore,according to this laminated structure, the reliability of the flexibleframe 100 may be improved.

FIG. 14 is a conceptual view showing still another example of a flexibledisplay unit 30 having the flexible frame 100 of the present disclosure.

Referring to FIG. 14, the flexible display 31 and the flexible frame 100may be coupled by a bonding portion 32 interposed therebetween. For thebonding portion 32, an OCA (optically clear adhesive) may be used.

The holes 110′ of the flexible region 110 are filled with a siliconportion 33 with an elastically deformable material. As shown in thedrawing, the silicon portion 33 may be bought into contact with aportion of the bonding portion 32 exposed through the holes 110′. Thesilicon portion 33 may form the same plane as the rear surface of theflexible frame 100.

The silicon portion 33 may be integrally formed with the flexible frame100 by insert injection. In other words, the silicon portion 33 may befilled between the holes 110′.

The silicon part 33 is formed integrally with the flexible frame 100,thereby allowing the silicon portion 33 to increase a restoring force ofthe flexible frame 100 itself. In other words, in this laminatedstructure, a restoring force of the flexible portion 100 acts on arestoring force of the silicon portion 33 at the same time. Therefore,this laminated structure has a larger restoring force compared to thelaminated structure shown in FIG. 12.

Moreover, this laminated structure has an advantage capable of reducinga thickness of the silicon portion (the first portion 23 a in FIG. 13)disposed on the flexible region 110 and the rigid portion 120.Therefore, when the present flexible display unit 30 is designed to havethe same height as that of the flexible display unit 20 shown in FIG.13, a thickness of the flexible frame 100 may be made thicker.Therefore, the present laminated structure has an advantage in that ayield strain of the flexible frame 100 compared to the laminatedstructure shown in FIG. 13 can be increased.

For reference, the laminated structures illustrated in FIGS. 12 to 14may be applicable not only to the flexible frame 100 shown in FIG. 1 butalso to various modified examples of the flexible frame. For example,the present laminated structures may be applicable to a flexible frame400 (refer to FIG. 18) which will be described later.

FIG. 15 is a conceptual view for explaining a restoring mechanism of theflexible display unit 10 by the lamination of the flexible frame 100 andthe flexible display 11 of the present disclosure.

In this drawing, as illustrated in FIGS. 1 to 11, the second flexibleportion 112 is formed on both sides of the first flexible portion 111 toform the flexible region 110. The first flexible portion 111 isconfigured to be bendable up to a state having a maximum first curvatureby the first holes 111′ repeatedly formed, and the second flexibleportion 112 is configured to be bendable up to a state having a maximumsecond curvature by the second holes 112′ repeatedly formed. Here, thefirst curvature is set to be larger than the second curvature. In otherwords, a first curvature radius of the first flexible portion 111 issmaller than a second curvature radius of the second flexible portion112 in a state where the first and second flexible portions 111, 112 arebent to the maximum.

Referring to FIG. 15A, in a first state where no external force isapplied, a interval between the first holes 111′ and an interval betweenthe second holes 112′ are maintained constant in an unchanged manner. Inthe first state, the flexible frame 100 is disposed flat, and theflexible display 11 laminated therewith is also disposed flat. In otherwords, in the first state, the flexible display unit 10 is disposedflat.

Referring to FIG. 15B, a spacing interval between the first and secondholes 111′, 112′ is extended or reduced in a second state in which theflexible display unit 10 is bent to the maximum by an external force.The flexible frame 100 and the flexible display 11 are laminated witheach other and an entire length of the flexible frame 100 is notchanged, and thus when there is a portion where a spacing intervalbetween the holes is extended, a portion where the spacing intervalbetween the holes is reduced occurs.

As a result, a restoring force is generated due to a property that thefirst and second holes 111′, 112′, which are extended or reduced, returnto an original spacing interval in the flexible frame 100. By therestoring force, the flexible display unit 10 returns to the firststate.

Specifically, a spacing interval between the first holes 111′ formed onthe first flexible portion 111 is increased, and a restoring force fordecreasing the spacing interval between the first holes 111′ isgenerated in the first flexible portion 111. A spacing interval betweenthe second holes 112′ formed on the second flexible portion 112 isdecreased, and a restoring force for increasing the spacing intervalbetween the second holes 112′ is generated in the second flexibleportion 112.

The flexible frame 100 is preferably configured to have greaterelasticity than the flexible display 11. According to this, when theflexible frame 100 is bent, a restoring force of the flexible display 11itself is added to a restoring force of the flexible frame 100, therebyimproving a restoring force of the flexible display unit 10.

On the other hand, the first curvature is preferably designed to betwice or more the second curvature. In other words, a second curvatureradius of the second flexible portion 112 is preferably designed to betwice or more than a first curvature radius of the first flexibleportion 111 in a state where the first and second flexible portions 111,112 are bent to the maximum.

Hereinafter, it will be described which material is suitable for use inthe flexible frame 100.

Yield Elastic Yield Type strength modulus strain Thickness Beta Titanium 850 MPa 80 0.01063 0.3 mm Titanium Gr2  850 MPa 110 0.00773 0.3 mm STS301 EH 1275 MPa 200 0.006375 0.3 mm

The above table shows a yield strength and a yield strain of titaniumand stainless steel.

The relationship between stress and strain seen in a particular materialmay be represented by a stress-strain curve of the material. Thematerial has a unique stress-strain curve, where the slope denotes amodulus of elasticity.

Yield strength refers to a force capable of withstanding until amaterial is no longer restored when applying a force to the material.Yield strain refers to a strain at yield strength. Furthermore, an areaunder the stress-strain curve up to a yield point denotes a restoringforce. Therefore, it is seen that as the area increases, a restoringforce of the material increases.

In order to allow the flexible frame 100 to withstand repeated bendingand restoration, it is preferable that the flexible frame 100 is made ofa material having a predetermined level of yield strength and a highyield strain and restoring force.

As can be seen from the table, stainless steel has a high yield strengthbut a small yield strain, and thus is not suitable for being applied tothe flexible frame 100 in which bending and restoring are repeated. Onthe contrary, it can be seen that titanium has a yield strength lowerthan that of stainless steel but has a predetermined level of yieldstrength and a high yield strain. Accordingly, when the flexible frame100 is formed of a titanium material, it may be bent without breakage,thereby implementing a restorable characteristic.

Various titanium materials such as Beta Titanium and Titanium Gr2 may beused to make the flexible frame 100. Titanium Gr2 is a good choice whenlooking for relatively inexpensive titanium with a high yield strengthand restoring force compared to stainless steel.

In addition, stainless steel is a ferromagnet, which can affectsurrounding electronic components, while titanium does not have magneticproperties and thus is more suitable for use in an electronic devicesuch as mobile terminal 1000 in which electronic components areintegrated.

FIG. 16 is a conceptual view showing an example of a mobile terminal1000 to which the flexible display unit 10 having the flexible frame 100shown in FIG. 1 is applied.

Referring to FIG. 16, the mobile terminal 1000 includes a first body1100 and a second body 1200 that are configured to be relativelymovable. The first body 1100 and the second body 1200 may have the samesize.

FIG. 16A shows a first state in which the first body 1100 and the secondbody 1200 are arranged in parallel, and FIG. 16B shows a second state inwhich the second body 1200 is folded over the first body 1100. Themobile terminal 1000 is configured to freely modify its form from afirst state to a second state, or from a second state to a first state.

In order to implement this, the first body 1100 and the second body 1200may be respectively connected to the hinge portion 1300, and configuredto be rotatable with respect to the hinge portion 1300.

Referring to FIG. 16A, the flexible display unit 10 is disposed on onesurface of the first body 1100 and on one surface of the second body1200. In other words, the flexible display unit 10 is disposed over thefirst body 1100 and the second body 1200, thereby implementing a largescreen. The flexible display unit 10 is disposed to cover the hingeportion 1300.

The first flexible portion 111 of the flexible frame 100 is disposed tocover the hinge portion 1300, and the second flexible portion 112 isdisposed to cover the end portions of the first body 1100 and the secondbody 1200. The first flexible portion 111 may be formed in the middleportion of the flexible frame 100. The rigid portion 120 is disposed tocover the first body 1100 and the second body 1200 to support theflexible display 11 in a flat state.

Referring to FIG. 16B, when the second body 1200 is folded over thefirst body 1100, the flexible display unit 10 is bent by an externalforce. The first flexible portion 111 is bent at a first curvature, thesecond flexible portion 112 is bent at a second curvature, and the rigidportions 120 are arranged to face each other. Accordingly, the portionsof the flexible display 11 supported by the rigid portion 120 arearranged to face each other.

The center of a curvature radius of the first flexible portion 111 islocated in an inner space formed by the folding of the flexible frame100 and the center of a curvature radius of the second flexible portion112 is located in an outer space formed by the folding of the flexibleframe 100, and thus the flexible frame 100 is bent in a shape as shownin FIG. 16B. Considering such a shape change, recessed spaces 1100′,1200′ in which a part of the flexible display unit 10 corresponding tothe first and second flexible portions 111, 112 can be received may beformed in the first and second bodies 1100, 1200.

As shown in the drawing, the recessed spaces 1100′, 1200′ may beconfigured to be blocked by mechanically interlocking the first andsecond bodies 1100 and 1200 with the hinge portion 1300 in the firststate shown in FIG. 16A. In other words, the recessed spaces 1100′,1200′ may be formed only in the second state shown in FIG. 16B.

On the other hand, in the second state shown in FIG. 16B, the first andsecond bodies 1100, 1200 are subjected to a force to return to the firststate shown in FIG. 16A by a restoring force of the flexible displayunit 10. Accordingly, in order to maintain the second state shown inFIG. 16B, the first body 1100 and the second body 1200 may be providedwith magnet portions 1400′, 1400 which exert attractive forces on eachother.

The magnet portions 1400′, 1400′ may be disposed at each end portion ofthe first and second bodies 1100, 1200 to face each other in a foldedstate. The attractive force exerted by the magnet portions 1400′, 1400is set to be larger than a restoring force of the flexible display unit10. Therefore, the mobile terminal 1000 cannot return to the state ofFIG. 16A only by a restoring force of the flexible display unit 10.

However, when a force for moving the first body 1100 and the second body1200 away from each other is (instantaneously) applied, and a sum forceof the force and a restoring force of the flexible display unit 10 islarger than an attractive force of the magnet portions 1400′ 1400, themobile terminal 1000 can be returned to the state of FIG. 16A only bythe restoring force of the flexible display unit 10 thereafter.

Hereinafter, various other examples will be described in order to showthat the flexible frame 100 can have various forms.

FIG. 17 is a view showing another example of a flexible frame 400 of thepresent disclosure, and FIG. 18 is a conceptual view showing a state inwhich each flexible portion of the flexible frame 400 shown in FIG. 17is bent at a maximum curvature, and FIG. 19 is a conceptual view showinga Y direction area change of the flexible frame 400 shown in FIG. 17,and FIG. 20 is an enlarged view of a flexible region 410 shown in FIG.17.

Referring to FIGS. 17 to 20, the flexible frame 400 includes a flexibleportion 411, a first rigid portion 420′ and a second rigid portion 420″disposed on both sides of the flexible portion 411, a first boundaryportion 412′ disposed between the flexible portion 411 and the firstrigid portion 420′ and a second boundary portion 412″ disposed betweenthe flexible portion 411 and the second rigid portion 420″. Here, theflexible portion 411 and the first and second boundary portions 412′,412″ form the flexible region 410.

The flexible region 410 is configured to be bent with respect to the Ydirection. Here, the X direction corresponds to a widthwise direction ofthe flexible frame 400, and the Y direction corresponds to a lengthwisedirection of the flexible frame 400.

The flexible portion 411 is configured to be bendable up to a statehaving a maximum first curvature. First holes 411′ are repeatedly formedon the flexible portion 411 to implement the bending of the flexibleportion 411. In other words, flexibility may be generated on theflexible portion 411 due to the first holes 411′, and the flexibleportion 411 may be bent up to a state having the maximum firstcurvature.

The first holes 411′ are repeatedly formed along the X and Y directionsintersecting each other. The first holes 411′ are extended in anelongated manner in the X direction.

First and second rigid portions 420′, 420″ are respectively disposed onboth sides of the flexible portion 411 in the Y direction. The first andsecond rigid pots 420′, 420″ may be formed in a plane that is hardlybent by an external force. Intentional holes are not formed on the firstand second rigid portions 420′, 420″ to implement bending. In a statewhere the flexible portion 411 is bent to the maximum, the first andsecond rigid portions 420′, 420″ are arranged to face each other.

Between the flexible portion 411 and the first rigid portion 420′, andbetween the flexible portion 411 and the second rigid portion 420″,first and second boundary portions 412′, 412″ for smoothly connectingthem are respectively formed. The second and third holes 412′, 412″ areformed on the first and second boundary portions 412′, 412″ so that thefirst and second boundary portions 412′, 412″ are bendable with respectto the Y direction. The second and third holes 412′, 412″ may beextended in an elongated manner in the X direction and disposed inparallel with the first holes 411′.

A degree of bending of the first and second boundary portions 412′, 412″may be achieved by changing a total area occupied by the second andthird holes 412′, 412″ per unit area of the first and second boundaryportions 412′, 412″.

The first and second boundary portions 412′, 412″ are configured to beless bendable than the flexible portions 411. For this purpose, a totalarea occupied by the second and third holes 412′, 412″ per unit area inthe first and second boundary portion 412′, 412″ is set to be smallerthan a total area occupied by the first holes 411′ per unit area in theflexible portion 411.

For this purpose, a length of each of the second and third holes 412′,412″ may be set to be smaller than that of the first holes 411′.Alternatively, a spacing interval between the second and third holes412′, 412″ may be set to be larger than that between the first holes411′.

The second and third holes 412′, 412″ may be arranged in a zigzag mannerwhile partially overlapping each other along the Y direction. As shownin the drawing, the second and third holes 412′, 412″ arranged along theX direction are disposed in the Y direction directly above or below aregion between the second and third holes 412′, 412″ arranged along theX direction (a region where an inherent material of the rigid flexibleframe 400 remains).

Here, a length of a mutually overlapping portion between the second andthird holes 412′, 412″ along the Y direction is set to be smaller thanthat of a mutually overlapping portion of the first holes 411′.

A maximum curvature at one end portion of the first and second boundaryportions 412′, 412″ adjacent to the flexible portion 411 may be set tobe greater than a maximum curvature at the other end portion of thefirst and second bound portions 412′, 412″ adjacent to the first andsecond rigid portions 420′, 420″. In other words, the maximum curvatureat one end portion of the first and second boundary portions 412′, 412″may be set to be smaller than the first curvature, and the maximumcurvature at the other end portion of the first and second boundaryportions 412′, 412″ may be set to be greater than zero.

To this end, a length of a hole adjacent to the flexible portion 411 ofamong the second and third holes 412′, 412″ may be set to be larger thanthat of a hole adjacent to the first and second rigid portions 420′,420″. Alternatively, a spacing interval between the second and thirdholes 412′, 412″ at a portion adjacent to the flexible portion 411 maybe set to be smaller than that between the second and third holes 412′,412″ at a portion adjacent to the first and second rigid portions 420′,420″.

Alternatively, the second and third holes 412′, 412″ may be randomlyarranged under the condition that a total area occupied by the secondand third holes 412′, 412″ per unit area in the first and secondboundary portions 412′, 412″ is set to be smaller than a total areaoccupied by the first holes 411′ per unit area in the flexible portion411.

FIG. 18 shows a view in which the flexible portion 411 is bent to themaximum. As shown in the drawing, the center of a curvature radius ofthe flexible portion 411 is located in an inner space formed by thefolding of the flexible frame 400.

FIG. 21 is a conceptual view showing an example of a mobile terminal2000 to which the flexible display unit 40 having the flexible frame 400shown in FIG. 17 is applied.

The flexible display unit 40 is formed in an elastically deformablemanner, and includes a flexible display 41 and the foregoing flexibleframe 400. The flexible display 41 and the flexible frame 400 may becoupled to each other by a laminated structure described above in FIGS.12 to 14.

FIG. 21A shows a first state in which the flexible display unit 40 isfolded flat on one surface of the terminal body 2100, and FIG. 21B showsa second state in which the flexible display unit 40 is folded so thatpart thereof is disposed on the other surface of the terminal body 2100.The flexible display unit 40 is configured to freely modify its formfrom a first state to a second state, or from a second state to a firststate.

In order to implement this, the first rigid portion 420′ is configuredto be attached onto one surface of the terminal body 2100, and the firstboundary portion 412′, the flexible portion 411, the second boundaryportion 412″, and the second rigid portion 420″ are configured to bedetachable from the terminal body 2100.

A round portion 2100′ is formed at one end portion of the terminal body2100 to guide the modification of its shape such that the first boundaryportion 412′, the flexible portion 411 and the second boundary portion412″ can be bent in a corresponding manner to the round portion 2100′. Adegree of bending, namely, a curvature, of the round portion 2100′, ispreferably set to be equal to or smaller than a first curvature which isthe maximum curvature at which the flexible portion 411 can be bent.

When the first boundary portion 412′, the flexible portion 411 and thesecond boundary portion 412″ are bent in a corresponding manner to theround portion 2100′, the second rigid portion 420″ is disposed to coverthe other surface of the terminal body 2100. A recess portion 2100″capable of accommodating a portion of the flexible display unit 40corresponding to the second rigid portion 420″ may be formed on theother surface of the terminal body 2100. In a state where a portion ofthe flexible display unit 10 corresponding to the second rigid portion120 is accommodated in the recess portion 2100″, an upper surface of theone portion may form the same plane as the other surface of the terminalbody 2100.

On the other hand, in the second state shown in FIG. 21B, the flexibledisplay unit 40 is subjected to a force of returning to the first stateshown in FIG. 21A by a restoring force of the flexible frame 400.Accordingly, in order to maintain the second state shown in FIG. 21B,one end portion of the flexible display unit 40 and the terminal body2100 may be provided with magnet portions 42, 2200 which exertattractive forces on each other.

The magnet portions 42, 2200 are provided on the other side of thesecond rigid portion 420′ and the terminal body 2100 so that theflexible display unit 40 can be dispose to face each other in a foldedstate. The attractive force exerted by the magnet portions 42, 2200 isset to be larger than a restoring force of the flexible display unit 40.Therefore, the flexible display unit 40 cannot return to the state ofFIG. 21A only by a restoring force of the flexible display unit 40.

However, when a force for detaching the second rigid portion 420″ fromthe other side of the terminal body is (instantaneously) applied by auser, and a sum force of the force and a restoring force of the flexibledisplay unit 40 is larger than an attractive force due to the magnetportions 42, 2200, the flexible display unit 40 can be returned to thestate of FIG. 21A only by the restoring force of the flexible displayunit 40 thereafter.

FIG. 22 is a conceptual view showing an example of a mobile terminal3000 to which a flexible display unit 50 having another example of theflexible frame 500 of the present disclosure is applied.

Referring to FIG. 22A, the flexible frame 500 of the present example maybe provided with two flexible regions 510′, 510″. The flexible region510′ at an upper portion of the drawing is the same as a structure ofthe flexible frame 100 shown above in FIG. 1, and the flexible region510″ at a lower portion of the drawing is the same as a structure of theflexible frame 400 shown above in FIG. 17. Therefore, the description ofthe structure of the flexible frame 500 will be substituted by theearlier description.

Referring to FIG. 22B, a mobile terminal 3000 includes a first body3100, a second body 3200 and a third body 3300 which are configured tobe relatively movable. The first body 3100, the second body 3200, andthe third body 3300 may have the same size.

In a first state in which the first body 3100, the second body 3200 andthe third body 3300 are unfolded flat, the flexible display unit 50 aredisposed over the first body 3100, the second body 3200, and the thirdbody 3300 to constitute a large screen.

In a second state in which the first body 3100, the second body 3200 andthe third body 3300 are sequentially folded as shown in FIG. 22B, theflexible display unit 50 is also folded in a corresponding mannerthereto.

The mobile terminal 3000 is configured to freely modify its form from afirst state to a second state, or from a second state to a first state.

In order to achieve this, the first body 3100 and the second body 3200may be respectively connected to a first hinge portion 3000′ to berotatable with respect to the first hinge portion 3000′, and the secondbody 3200 and the third body 3300 may be respectively connected to asecond hinge portion 3000″ to be rotatable with respect to the secondhinge portion 3000″.

The description of each structure will be substituted by the earlierdescription of FIGS. 16 and 21.

FIG. 23 is a conceptual view showing still another example of theflexible frame 600 of the present disclosure.

Referring to FIG. 23, at least one or more flexible portions 611, 612,613, 614, 615 may be provided in the flexible frame 600. Here, theflexible portions 611, 612, 613, 614, 615 may have an asymmetric shape.

In other words, in FIG. 1, the second flexible portions 112 having thesame maximum curvature are formed to have the same length on both sidesof the first flexible portion 111 to have a shape symmetrical withrespect to the center of the first flexible portion 111, but a shape ofthe flexible frame 100 is not limited to such a symmetric shape.

A degree to which each of the plurality of flexible portions 611, 612,613, 614, 615 is bendable to the maximum, namely, a maximum curvature,may be designed to have a different value. Furthermore, the lengths ofthe plurality of flexible portions 611, 612, 613, 614, 615 may bedesigned to be different.

In this drawing, it is shown that five flexible portions 611, 612, 613,614, 615 are designed to have different maximum curvatures, and theirlengths are also set to be different.

1. A flexible display unit, comprising: a flexible display formed to beelastically deformed; and a flexible frame coupled to a rear surface ofthe flexible display, wherein the flexible frame comprises: a flexibleportion in which first holes are repeatedly formed to be bendable up toa state having a maximum first curvature; and a rigid portion disposedon at least one side of the flexible portion, and wherein the flexibleframe is formed of a titanium material.
 2. The flexible display unit ofclaim 1, wherein when the flexible display is deformed, an intervalbetween the first holes is enlarged or reduced to apply a restoringforce to the flexible display.
 3. The flexible display unit of claim 1,wherein an adhesive portion is disposed between the flexible display andthe flexible frame, and a part of the adhesive portion is exposedrearward through the first holes.
 4. The flexible display unit of claim1, further comprising: an adhesive portion disposed on a rear surface ofthe flexible display; and a silicon portion disposed between theadhesive portion and the flexible frame, wherein the silicon portioncomprises: a first portion disposed on the flexible portion and therigid portion; and a second portion filled in the first holes.
 5. Theflexible display unit of claim 4, wherein the second portion forms thesame plane as the rear surface of the flexible frame.
 6. The flexibledisplay unit of claim 4, wherein the silicon portion is integrallyformed with the flexible frame by insert injection.
 7. The flexibledisplay unit of claim 1, further comprising: an adhesive portiondisposed between the flexible display and the flexible frame; and asilicon portion filled in the first holes.
 8. The flexible display unitof claim 7, wherein the silicon portion is brought into contact with apart of the adhesive portion exposed through the first holes.
 9. Theflexible display unit of claim 7, wherein the silicon portion forms thesame plane as the rear surface of the flexible frame.
 10. The flexibledisplay unit of claim 7, wherein the silicon portion is integrallyformed with the flexible frame by insert injection.
 11. The flexibledisplay unit of claim 1, wherein the flexible frame further comprises: aboundary portion in which second holes parallel to the first holes arerepeatedly formed between the flexible portion and the rigid portion,wherein a total area occupied by the second holes per unit area issmaller than a total area occupied by the first holes per unit area inthe flexible portion.
 12. The flexible display unit of claim 11, alength of each of the second holes is shorter than that of each of thefirst holes.
 13. The flexible display unit of claim 11, wherein thefirst and second holes are respectively formed in a repetitive manneralong a widthwise direction and a lengthwise direction of the flexibleframe intersecting each other, and an interval between the second holesextended in a widthwise direction of the flexible frame is larger thanthat between the first holes.
 14. A flexible display unit, comprising: aflexible display formed to be elastically deformed; and a flexible framecoupled to a rear surface of the flexible display, wherein the flexibleframe comprises: a first flexible portion in which first holes arerepeatedly formed to be bendable up to a state having a maximum firstcurvature; a second flexible portion in which second holes parallel tothe first holes are repeatedly formed on one side of the first flexibleportion, and configured to be bendable up to a state having a maximumsecond curvature; and a third flexible portion in which third holesparallel to the first holes are repeatedly formed on the other side ofthe first flexible portion, and configured to be bendable up to a statehaving a maximum third curvature; and wherein the first curvature is atleast two times the second and third curvatures.
 15. The flexibledisplay unit of claim 14, wherein a total area occupied by the firstholes per unit area in the first flexible portion is larger than a totalarea occupied by the second holes per unit area in the second flexibleportion and a total area occupied by the third holes per unit area inthe third flexible portion.
 16. The flexible display unit of claim 14,wherein the second flexible portion and the third flexible portion areformed symmetrically with respect to the first flexible portion so thatthe second curvature and the third curvature are the same.
 17. Theflexible display unit of claim 14, wherein first and second rigidportions for supporting the flexible display in a flat state aredisposed on one side of the second flexible portion and the thirdflexible portion, respectively, and the first and second rigid portionsare disposed to face each other while the first to third flexibleportions are bent at the first to third curvatures, respectively. 18.The flexible display unit of claim 17, further comprising: a firstboundary portion in which fourth holes are repeatedly formed between thesecond flexible portion and the first rigid portion, wherein a totalarea occupied by the fourth holes per unit area is smaller than a totalarea occupied by the second holes per unit area in the second flexibleportion; and a secondary boundary portion in which fifths hole arerepeatedly formed between the third flexible portion and the secondrigid portion, wherein a total area occupied by the fifth holes per unitarea is smaller than a total area occupied by the third holes per unitarea in the third flexible portion.
 19. The flexible display unit ofclaim 18, further comprising: a first connecting portion in which sixthholes parallel to the first and second holes are repeatedly formedbetween the first flexible portion and the second flexible portion,wherein a total area occupied by the sixth holes per unit area issmaller than a total area occupied by the first holes per unit area inthe first flexible portion and larger than a total area occupied by thesecond holes per unit area in the second flexible portion; and a secondconnecting portion in which seventh holes parallel to the first andthird holes are repeatedly formed between the first flexible portion andthe third flexible portion, wherein a total area occupied by the seventhholes per unit area is smaller than a total area occupied by the firstholes per unit area in the first flexible portion and larger than atotal area occupied by the third holes per unit area in the thirdflexible portion.
 20. A mobile terminal, comprising: a terminal bodyformed of an elastically deformable material; a flexible display unitcoupled to one surface of the terminal body and configured to beelastically deformable together with the terminal body; and magnetportions provided at both ends of the terminal body disposed to faceeach other in a state where the first to third flexible portions arebent at the first to third curvatures, respectively, to exert attractiveforces on each other, wherein the flexible display unit comprises: aflexible display formed to be elastically deformed; and a flexible framecoupled to a rear surface of the flexible display, wherein the flexibleframe comprises: a first flexible portion in which first holes arerepeatedly formed to be bendable up to a state having a maximum firstcurvature; a second flexible portion in which second holes parallel tothe first holes are repeatedly formed on one side of the first flexibleportion, and configured to be bendable up to a state having a maximumsecond curvature; and a third flexible portion in which third holesparallel to the first holes are repeatedly formed on the other side ofthe first flexible portion, and configured to be bendable up to a statehaving a maximum third curvature, wherein the first curvature is atleast two times the second and third curvatures, wherein first andsecond rigid portions for supporting the flexible display in a flatstate are disposed on one side of the second flexible portion and thethird flexible portion, respectively, and wherein the first and secondrigid portions are disposed to face each other while the first to thirdflexible portions are bent at the first to third curvatures,respectively.